1. Field of the Invention
The present invention relates to an apparatus for opening and closing a cover for a keyboard-type musical instrument such as an electronic piano and the like. More particularly, the invention relates to a sliding cover which is easier to assemble and provides for a smoother operating device.
2. Description of the Relevant Art
Shown in FIGS. 8 through 11, a conventional apparatus including a member c having on its upper face a rack "a" and a guide groove b is fixed with screws on the inner side surface of a plate e of a musical instrument case b. Shaft g is provided at the rear portion of a sliding cover f which covers the keyboard. Pinions h are provided on both end portions of the rotary shaft g. Each end of the rotary shaft g is slidably fitted into the pair of right and left guide grooves b.
One of the major problems associated with the known cover members is the possibility that the members are longitudinally or vertically misaligned when they are fixed with screws. If this occurs, engagement between the moving members becomes uneven, and the opening and closing of the sliding cover cannot be accomplished smoothly and evenly.
The present invention overcomes the above-mentioned alignment problem by providing rack and pinion guide grooves which are always in a predetermined symmetrical position on the right and left side-plates. As a result, the engagement between the racks and the pinions is smooth and the sliding cover can be easily slid into place.